Refrigeration method



Nov. 28, 1939. G. s. LOY 2,181,855-

REFRIGERATION METHOD Original Filed April 50, 1937 INVENTOR GRHHkM 5. MgCLoyf ATTOR Y Patented Nov. 28, 1939 REFRIGERATION NIETHOD Graham S.McCloy, East Longmeadow, Mass, assignor to Westinghouse Electric &Manufacturing Company, East Pittsburgh, Pa., a corporation ofPennsylvania Application April 30, 1937, Serial No. 140,011 Renewed.lune l, 1939 r 6 Claims.

My invention relates to refrigeration apparatus and to a method ofrefrigeration and particularly to the removal of air or othernon-condensable gases from a refrigerating system.

In the charging of a refrigerating system and particularly of arefrigerating system of the compression type, it is necessary to removeair and other non-condensable gases from the system for various reasons.The air and non-condensable gases must be removed because they willcollect in the high pressure side of the system and cause unduly highhead pressures. Furthermore, the presence of air or othernon-condensable gases will sometimes cause oxidation of parts of therefrigerating system. In addition, in compression refrigerationapparatus particularly of the hermetically sealed type wherein the motorand compressor'are contained within the sealed casing and the motorwindings are subjected to an atmosphere of refrigerant and lubricant,any air or other non-condensable gases which are present in the systemmay themselves attack the windings or may combine with the refrigerantor lubricant to form moisture which will in turn attack the windings orfreeze up in some part of the system.

It has, therefore, been necessary, before charging refrigerating systemswith lubricant and refrigerant, to evacuate the systems in some manner.The method used for evacuating the sys- 30 terns has been to pump theair out of the system before charging. Such a method has two maindefects. First, it is practically impossible to pump a sufliciently highvacuum to completely remove all the air and non-condensable gases fromthe system. Secondly, the equipment required for pulling a high vacuumon refrigeratin'g systems is necessarily expensive, cumbersome and slowin operation. Furthermore, air and non-condensable vapors which arecontained in the refrigerant and oil are not removed by such evacuatingequipment. I

It is therefore an object of my invention to provide improved apparatusand an improved method for removing air and non-condensable gases from arefrigerating system.

It is another object of my invention to provide a method of removing airand non-condensable gases from a refrigerating system wherein thecompressor of the refrigerating system performs the work of removing theaforesaid non-condensable gases and expensive and cumbersome evacuatingapparatus is, therefore, dispensed with.

It is another object of my invention to provide a means and method ofremoving non-condensable gases from a refrigerating system which vice isutilized to control the flow of refrigerant 10 from the high to the lowpressure side of the system.

It is a further object of my invention to re- I move the air or othernon-condensable gases which are present in the refrigerant and lubricantwith which the system is charged.

These and other objects are effected by my invention as will be apparentfrom the following description and claims taken in connection with theaccompanying drawing, forming a part of go this application, in whch:

Fig. 1 diagrammatically shows a refrigerating system of the compressiontype' in which a hermetically sealed motor compressor unit is utilizedand illustrates an application of my invention to this typeofrefrigerating system; and

' Fig. 2 shows my invention applied to a float valve machine.

Referring specifically to the drawing for a detailed description of myinvention, numeral II designates a hermetically sealed casing whichencloses a motor l2 which drives a. reciprocating compressor l3. Gas isdischarged at highpressure from the compressor through the conduit Mwhich extends through the sealed casing II and joins a conduit l5 whichconveys high pressure refrigerant gas to a condenser I6. Refrigerant gasis cooled and condensed in the condenser IS, a motor driven fan I!serving to force cool air over the condenser for this purpose. Condensedliquid refrigerant then passes through a conduit l8 to an open tube l9of restricted diameter and considerable length, sometimes referred to asa capillary tube. The capillary tube controls the flow of liquidrefrigerant from the condenser IE to a flooded evaporator 2| and permitsthe circulation of some gaseous fluid therethrough. The floodedevaporator 2| is connected to the interior of the hermetically sealedcasing II which is subjected to the low pressure of the compressor by aconduit 22. Refrigerant is, therefore, vaporized in the evaporator 2|and returned to the interior of the casing ll, whereby the vaporizedrefrigerant cools the evaporator 2|. The compressor I3 is provided witha port 23 through the port 23 to the compressor and the cycle is thenrepeated. Suitable control mechanisms may be provided for controllingthe operation of the motor and compressor in response to temperature ofthe evaporator. Since these control devices are Well known in the art,no description thereof isdeemed necessary.

In accordance with my invention, a container 25 is connected into thehigh pressure conduit I5 by a conduit 26 in such a manner that thecontainer 25 is disposed above the conduit I5 containing high pressurerefrigerant vapor.

The refrigerating system is first charged with refrigerant andlubricant, the exact amount to be charged being very carefully measuredand placed in the system. The system at this time also contains air andother gases which are not readily condensable at ordinary temperatures.The motor I2 is then started and the compressor I3 pumps bothrefrigerant vapor and non-condensable gases into the conduit I5. Themixture of refrigerant vapor and non-condensable gases will circulatethrough the system as long as there are not any liquid traps therein,and in a system as shown in Fig. 2 where there are liquid traps, suchas, for example, where a float valve I0 is used between the condenserand the evaporator, the non-condensable gases will collect in the highside of the system, and if the tank 25 is properly positioned as shownin Fig. 2, above the float chamber, the non-condensable gases will becollected in the tank. In the mixture of refrigerant and non-condensablegases which is pumped by the compressor I3 into the conduit I5, therefrigerant vapor is in a super-heated gaseous state. The mixture ofsuperheated refrigerant gas and non-condensable gases fills the tank 25passing through the conduit 26 into the tank. The tank 25 is exposed tothe ambient air which is relatively cool and, since the tank obviouslyhas considerable surface, the refrigerant gas loses its superheat andlatent heat, is condensed, and returns by gravity to the conduit I5 inthe form of liquid through the connecting tube 26. The air and othernon-condensable gases, however, remain in the tank as there is nothingto force them out of the tank. As condensation of the refrigerant vaporoccurs, the partial pressure of the refrigerant is reduced and thepressure in the tank 25 is reduced so that a flow of more superheatedrefrigerant gas and non-condensable gases occurs through the connectingtube 26 into the tank 25. There is, therefore, a counterfiow of amixture of refrigerant gas and non-condensable gases relative tocondensed refrigerant liquid through the connecting tube 26. I havefound that a tube of approximately of an inch diameter or larger issuitable for the connecting tube 26. The compressor I3 is operated untilall the air and non-condensable gases in the refrigerating system havebeen transferred to the tank 25, the tank preferably being sufiiclentlylarge to contain all of the air and noncondensable gases at the pressureat which they are present in the tank 25. When the compressor I3 hasoperated a suflicient length of time to transfer all the air andnon-condensable gases to the container 25, the tube 26 is pinched offand soldered and the tank 25 is removed and re-used on another system.The only loss of refrigerant which occurs is the small amount ofsaturated gaseous refrigerant which is necessarily present in the tankwith the non-condensable air and other gases when the tank is removedfrom the system.

It is obvious that the system shown in the drawing and described hereinis diagrammatic and that suitable fittings may be utilized to connectthe tank 25 to'the system and furthermore that the invention isapplicable to many other types of refrigerating systems. It will beapparent from the foregoing description that I have provided a means andmethod of removing air and non-condensable gases from a closedrefrigerating system, including the refrigerant and lubricant therein,which requires very little apparatus and which may be readily used inthe field. Furthermore, it is obvious that substantially all the air andnon-condensable gases may be easily removed from the system merely bycontinuously operating the compressor for a period of time sufl'icientto collect thenon-condensable gases. Such a system obviously makes itunnecessary to utilize expensive and cumbersome evacuating apparatus toremove the air.

and other non-condensable gases from the refrigerating system prior tocharging and the great expense as well as the time of connecting thesystem up to the evacuating devices and the time of evacuation aretherefore saved.

While I have shown my invention in several I forms, it will be obviousto those skilled in the art that it is not so limited, but issusceptible of various other changes and modifications without departingfrom the spirit thereof, and I desire.

therefore, that only such limitations shall be placed thereupon as areimposed by the prior art are non-condensable at ordinary temperatures,

connecting to the high pressure side of the system a container of a sizesumcient to hold, at condenser pressure, the non-condensable gasescontained in the system during said charging, and disposing saidcontainer above the point of its connection to the system, operating thecompressor to effect flow of a mixture of non-condensable gases andrefrigerant vapor at condenser pressure into said container, which saidcontainer is maintained at sufliciently low temperature to condense saidrefrigerant vapor at condenser pressure, for a period of time sufllcientto collect the non-condensable gases in said container, the refrigerantcondensed in said container being drained by gravity into the system,shutting ofi communication between the refrigerating system and saidcontainer, and disconnecting said container from the system while thenon-condensable gases collected in the container are retained therein.

2. The combined method of charging a refrigerating system and effectingthe removal of the non-condensable gases initially contained therein,said system including an evaporator; a compressor, a condenser, and anexpansion device of a type which permits circulation of some gaseousfluid therethrough, which method comprises charging the system withrefrigerant while the system contains gases which are non-condensable atordinary temperatures, connecting to the system between the compressorand the condenser a container of a size suflicient to hold, at condenserpressure, the non-condensable gases contained in the system during saidcharging and disposing said container above the point of its connectionto the system, operating the compressor to eifect circulation of gaseousfluid through the system and flow of a mixture of non-condensable gasesand refrigerant vapor into said container at condenser pressure, whilesaid container is maintained at sufficiently low temperature to condensesaid refrigerant vapor at condenser pressure, for a period of timesufficient to collect the non-condensable gases in said container, therefrigerant condensed in said container being drained by gravity intothe system, shutting off communication between the refrigerating systemand said container, and disconnecting said container from the system.

3. The combined method of charging a refrigerating system and effectingthe removal of the non-condensable gases initially contained there'- in,said system having high and low pressure sides and including anevaporator, a compressor, a condenser, and an expansion device, whichmethod comprises charging the system with refrigerant while the systemcontains gases which are non-condensable at ordinary temperatures,establishing communication between the high pressure side of the'systemand a container connected thereto and of suflicientsize to hold, atcondenser pressure, the non-condensable gases contained in the systemduring said charging, transferring said. non-condensable gases from thesystem to the container by operating the compressor to effect flow of amixture of noncondensable gases and refrigerant vapor at substantiallycondenser pressure into the container, condensing refrigerant vapor fromthe mixture in the container and returning the condensed refrigerant tothe system, and disconnecting said container from the system while thenon-condensable gases collected in the container are retained therein.

4. The combined method of charging a refrigerating system and effectingthe removal of the non-condensable gases initially contained therein,said system having high and low pressure sides and including anevaporator, a compressor, a condenser, and an expansion device of a typewhich permits circulation of some gaseous fluid therethrough, whichmethod comprises admitting a complete refrigerant charge to the systemwhile the latter contains gases which are non-condensable at ordinarytemperatures, connecting to the high pressure side of the system betweenthe compressor; and the condenser a container of a size sufficient tohold, at condenser pressure, the non-condensable gases contained in thesystem at the time of admitting said refrigerant charge thereto,transferring said non-condensable gases from the system to the containerby operating the compressor to effect flow of a mixture ofnoncondensable gases and refrigerant vapor at substantially condenserpressure into the container, and condensing refrigerant vapor in thecontainer and returning the condensed refrigerant to the system.

5. The combined method of charging a refrigerating system and eflfectingthe removal from the system of the non-condensable gases initiallycontained therein, said system having high and low pressure sides andincluding an evaporator, a compressor, a condenser, and a constantlyopen flow-controlling device of fixed restriction for regulating theflow of refrigerant between the condenser and the evaporator, whichmethod comprises admitting a refrigerant charge to the system,establishing communication between the system and a container connectedthereto, transferring non-condensable gases from the system to thecontainer by operating the compressor and effecting flow of a mixture ofrefrigerant vapor and non-condensable gases through the refrigeratingsystem including the flow-controlling device and also effecting flow ofa portion of said mixture into the container, and condensing refrigerantvapor from the mixture in the container and returning the condensedrefrigerant to the system.

6. The method of removing non-condensable gases from a refrigeratingsystem having high and low pressure sides and including an evaporator, acompressor, a condenser, and a constantly open flow-controlling deviceof fixed restriction for regulating the flow of refrigerant between thecondenser and the evaporator, which method comprises establishingcommunication between the high pressure side of the system anda-container connected'to said high pressure'side between the compressorand the condenser, transferring non-condensable gases from -the systemto the container by operating the compressor and effecting flow of amixture of refrigerant vapor and non-condensable gases through therefrigerating system including the flow-controlling device and alsoefiecting flow of a portion of said mixture into the container, andcondensing refrigerant vapor from the mixture in the container andreturning the condensed refrigerant to the system.

GRAHAM S McCLOY.

